Swiss Pat. No. 284,845 has already described a universal timepiece comprising, in addition to the usual time of day indicators, a rotatable dial driven by the movement and indicating relative to a fixed dial the time of day in different time zones of the earth. This watch is characterized by an arrangement enabling manual displacement of the rotatable dial independently from the usual time of day indicators, the whole in such a manner as to permit time setting of the rotatable dial. In this system the time setting arrangement includes in addition to a standard crown, an additional push piece intended to cause the rotatable dial to advance by means of a lever and a ratchet gear. Because of friction the displacements of the rotatable dial are not transmitted to the usual time of day indicators. Although it has been indicated that displacement of the rotatable dial may be effected by a crown replacing the push piece, there is nothing said as to how one might go about this in order to put it into practice.
The calendar-watch including two indicating means described in U.S. Pat. No. 3,765,162 is not, properly speaking, a universal timepiece since the hour indicators, which may be dephased relative to one another, each make a revolution in twelve hours, while a true universal timepiece presents, beside the usual hour, minute and second hands, a further hand making one revolution in twenty-four hours. Thus, in this construction, there is very simply provided a sliding coaxial coupling between the two hour wheels. Since a speed reducer is not necessary, the construction is simplified and the problem of correcting the indications is not present in the same manner as in the present invention. Should it be supposed that in the cited arrangement there is a simple speed reducing setting wheel between the indicator 6 and the indicator 7 (see FIG. 2 of the cited document) it will be necessary to arrange the sliding coupling between the indicator 6 fixed to wheel 3 and the teeth borne by this wheel and meshing with setting wheel 12, this leading to a complicated construction.
The observations which have just been made in the preceding paragraph may likewise by applied to U.S. Pat. No. 3,828,546.
Swiss Pat. No. 515.540 describes a timepiece comprising an additional time indicating means. If one of the figures of said patent shows the display of the date through a window in the dial, no explanation has been given as to the setting mechanism thereof from a single crown control which would likewise permit setting of the additional time indicator. Moreover, it must be noted that use has been made in this mechanism of a satellite wheel for driving the additional indicator while in the present invention a speed reducing setting wheel is arranged between first teeth fixed to the universal time indicator and second teeth fixed to the hours hand as will appear subsequently.
The timepiece according to this invention presents from the beginning the characteristics of a true universal timepiece since it possesses an indicator running on twelve hours and a further indicator running on twenty-four hours. The mechanism as provided enables setting of the universal time indicator by the crown and stem alone, and this through steps of one hour, the essential part of the invention residing in the system of the speed reducing gear which permits time setting and indexing of the universal time indicator. To attain this, means as set forth in the claims are employed.